Method of and apparatus for increasing the vacuum of turbines



Oct. 23, 1928. 1,688,413

A.DELAS FOR INCREASING THE VACUUM OF TURBINES METHOD OF AND APPARATUSFiled Oct. 19 1920 Patented Oct. 23, 1928.

UNITED stares 1,688,413 PATENT", OFFICE.)

ALBERT DELAS, or PARIS, FRANCE, Assienon T0 DELAS coivnnnsnncoaronnrron,

or NEW YORK, 1\T.. Y., AoonPonAmoN or DELAWARE.

METHOD OF AND APPARATUS FOR INCREASINGfT-HETVACU-UM' OI." NBBINES'.

Application filed October-19, 1920, Serial No. 417,990,311! in FranceIovemberifl, 1919.

The invention forming the subject matter of the present applicationrelates to steam tur-. bines andhas for its principal object to providea method, and means for carrying such method into practice, of reducingthe drop in pressure between the exit end of the turbine blades, orvanes, and the condenser.

The use of higher and higher expansions in the design and operation ofsteam turbines and consequently the use of very high vacuums at the exitof the last blades, in order considerably to diminish the specificconsumption of the turbines, has led to a diflicult problem. It has beenfound that the drop of pressure between the exit of the blades and thecondenser has a considerable detrimental influence upon the efficiencyof the turbine.

Attempts have been made to reduce this drop in pressure by designing ormaking the dimensions of the steam passages or channels such as toreduce the average flow of the steam or other fluid therethrough.Although this expedient is efficacious for a quiet steam flow,progressing at even speed and in parallel paths, experience has shownthat it is much less efiicient for steam which issues from the turbineblades in an agitated condition and in which there are whirls and eddiesdue, among other causes, to the changes of direction of flow to which itis subjected in the steam collector. I

Experiments madeon steam ejectors forming the subject matter of myFrench Patents 488,782, of Feb. 4, 1918, and 491,620, of Sept. 6,1918,.and my copending U. S. applications, Ser. Nos. 260,6O0y 260,601and 324,391, have shown that cooling of the walls of the diffuser causesthe sup ression of eddies, by the fixation of the incident molecules orpar ticles, with a consequent increase of efficiency. This increase ofefliciency' is greater than would be expected in view of the smallquantity of steam actually condensed.

The observations made in connection with the important improvements inejectors led to the solution of the problem of reducing the drop inpressure above mentioned in connection with turbines. .I solve thisproblem in the steam collectors and if desirable or necessary in theexhaust-pipes thereof.

The method may be best explained and understood. by describing one of.the formsof apparatus which may be employed to carry the same intopractice. Referring to the by cooling the walls I drawings whichillustrate what I now consider a preferred form of the invention:

Fig. I is a somewhat diagrammatic secprises a stator 1, provided withblades or vanes 2, and a rotor 3 provided with blades or vanes 4. Steam,or other elastic motive fluid, may be supplied to the turbine in any ofthe well known ways and, after having passed through the stages of themachine, passes into the exhaust steam collector5. From the collector orchamber 5 the steam passes to a condenser 10 through the dischargeopening 6 and any suitable connections. I condense the steam whichimpinges upon the walls of the collector 5 by cooling the walls of thelatter. One means for accomplishing this result may be constructedsubstantially as follows:

The steam collector or chamber 5 is pro vicled with a double envelope oracket 7 in which is established a circulation of cold water (or othercooling fluid) on all of its surface or only on the parts directlyimpinged by the stream of steamleaving the blades of the turbine. Thewater orcooling fluid may be introduced at 8 and discharged at 9 or viceversa.

This circulation may be extended to the piping or conduit connectingtheturbine to the condenser, should the shape of said pipe or conduit besuch as to produce or tend to produce eddies. I

The walls which are cooled should preferably be constructed of metal,of-good heat con ductivity such as aluminum, bronze, etc.

By virtue of the method and means above described the drop in pressurefrom the steam exit at the blades of the turbine to the condenser iseffectively and greatly' reduced.

What Inow consider the theory of operation 100 of my invention will beclearly apparentfrom the foregoing description in view of the disclosurein my copending applications and patents above mentioned.

lVhat I claim is 1. In combination, a. condenser, a turbine adapted tobe supplied with condensable elastic motive'fluid and to dischargethe'same into cated between the turbine and condenser, and

said condenser, an exhaust fluid collector lomeans whereby a coolingliquid is passed in 9:

2 1,eee,41s

of said collector." means forming a cooling jacket around at 2. Incombination, a condenser, a vaporleast a portion of said first namedmeans, the actuated turbine provided with means for inner Wall. of saidjacket being of metal of 5 conveying its exhaust to said condenser, andconip'a 'atively high heat conductivity.

least a portion of said first namedlneans. nature. 7 I a 3. Incombinatlon, a condenser, a vapor actuated turbine provlded with meansforcon- ALBERT DELAS.

contact With at least a portion of the Walls veying its exhaust to saidcondenser,- and means forming a cooling jacket around at In testimonyivhereoflhereto affix my sig- 1'

